Compound internal combustion engine



May 23, 1961 L. B. HARRIS COMPOUND INTERNAL COMBUSTION ENGINE 4 Sheets-Sheet 1 Filed Nov. 4, 1955 Emmi (571M May'23, 1951 L. B. HARRIS 2,984,966

COMPOUND INTERNAL COMBUSTION ENGINE Filed Nov. 4, 1 955 4 Sheets-Sheet 2 H68 F|G.9 FIGJO FIGQII 1 as s3; a 2 3' E i 37 37 4 9 /9 i 6 zsg 11 I I A I INVENTOR LEONARD BUSHE HARRIS I BY M ATTORNEY May 23, 1961 L. B. HARRIS COMPOUND INTERNAL COMBUSTION ENGINE 4 sheets-sheet 3 Filed Nov. 4, .1955

INVENTOR. Swami. PAHWMI L. B. HARRIS COMPOUND INTERNAL COMBUSTION ENGINE 4 Sheets-Sheet 4 or-ll May 23., 1961 Filed Nov. 4, 1955 CYU NDER IN VEN TOR. .Nwvm

sq Exunusf United States Patent O COMPOUND INTERNAL COlVIBUSTION ENGINE Leonard Bushe Harris, 41-14 40th St., Sunnyside, Long Island 4, N.Y.

Filed Nov. 4, 1955, Ser. No. 545,064

16 Claims. (Cl. 60-15) This invention relates to a compound internal combustic-n engine, and more particularly to a diesel engine. In a diesel engine air is highly compressed, and therefore heated, in the power cylinders, a charge of fuel is injected or sprayed into the heated air, ignition and combustion results, and hence the pistons are driven outward in their cylinders. This invention has for its general object the simplification and improvement of engines of this type by introducing certain novel features of operational sequence and construction calculated to materially increase the efficiency of the engine and produce an extended cycle.

In accordance with the invention the engine is provided with one or more pairs of cylinder-piston assemblies arranged in units of two adjacent cylinders, each cylinderpiston assembly having multiple-high and low pressure cylinders and pistons of different diameters arranged in tandem relation with each other, the pair of piston-cylinder combinations forming a unified pair to cooperate with each other in their joint functions of two-stagepower-stroke, two-stage-scavenging, air-compression, and two-stage-exhaust, these various functions occurring during each revolution of the crank shaft.

The cranks of the adjacent cylinders of each pair of cylinders are set cyclically opposite one another (out of phase by 180 degrees) in order to correctly time the sequence of the functions taking place alternately in the cylinders of each pair.

A prime object of the invention is to provide means for compounding the functions of a cooperating pair of cylinder assemblies of the type under discussion, each comprising high and low pressure cylinders and pistons arranged in tandem, so as to make possible an increase in the power output of the engine for the consumption of a given amount of fuel. This increase in power output is accomplished by causing the unspent exhaust gases from a high pressure cylinder to be admitted as a second stage power stroke to the low pressure step cylinder of the adjacent cylinder of the cooperating pair of cylinders.

In accordance with the present invention this is accomplished without having to utilize any valves, springs, cams, push rods, levers, or adjustment means for such elements, which are usually present in internal combustion engines. Instead of these conventional but troublesome elements, novel fully revolving communicating means are provided to control cooperation between each of a pair of adjacent cylinders. These communicating means are of appreciable volume when compared with the volume of the high pressure cylinders, so that they function not only to provide the desired communication but also to contain substantial volumes of the gases involved.

An object of the invention is to produce an engine with the aforementioned novel fully revolving communicating means between two adjacent cooperating cylinder units to provide for complete and immediate self-super-charging in a two-cycle engine even on the first revolution of 2,984,966 Patented May 23, 1961 the crank shaft, whether during air or electric starting or when operating on fuel, and without auxiliary supercharging means such as blowers or fans.

A feature of the motor of the instant invention is the functioning of the step or low pressure cylinders and pistons as second stage scavenging air compression pumps in conjunction with the crank case of the engine and the aforementioned fully revolving communicating means, so as to guarantee full capacity scavenging and super-charging to the high pressure cylinders on the first upstroke of their adjacent low pressure step pistons.

The operation of the engine of the present invention may be briefly described as follows, the cylinders of a given cooperating pair being designated respectively No. l and No. 2, each of these cylinders comprising a high pressure cylinder and piston in tandem relation with a larger diameter step or low pressure cylinder and piston. The crank case of No. 1 cylinder will be filled with air by suction on the upstroke of the No. 1 step piston. As this piston comes down the air in the crank case will be compressed, thus accomplishing the first stage of scavenging or pressure build-up. At the same time the down stroke of the No. 1 step piston will transfer the air compressed in the crank case to the No. 1 low pressure cylinder where, as the No. 1 step piston rises, the second stage of scavenging or pressure build-up will take place. As the up stroke of the No. 1 step piston continues the scavenging air will be forced into a scavenging manifold which communicates with No. 2 high pressure cylinder. Communication between this scavenging manifold and both the No. 1 low pressure cylinder and the No. 2 high pressure cylinder is accomplished by means of a rotating control element which, at an appropriate time synchronized with the exposure of the entrance ports to the No. 2 high pressure cylinder by the No. 2 high pressure piston, will permit the air contained within the scavenging manifold to enter the No. 2 high pressure cylinder.

After the No. 2 high pressure piston has compressed the air within the No. 2 high pressure cylinder and ignition and combustion are caused to take place, this constituting the No. 2 cylinder power stroke, the No. 2 high pressure cylinder will exhaust into an exhaust communicating manifold which also is in communication with the No. 1 low pressure cylinder. Here again a revolving control means synchronized with the movement of the various pistons, contains these exhaust gases, and, at an appropriate time, permits them to enter the No. 1 low pressure cylinder approximately at the time that the No. 1 low pressure piston is at the top of its stroke. These exhaust gases, still at an appreciable pressure, exert force on the No. 1 low pressure cylinder urging it toward the bottom of its stroke, thus producing the desired compounding. Thereafter the exhaust gases, now at appreciably lower pressure than they were at the end of the power stroke in the No. 2 high pressure cylinder, are permitted to exhaust to the atmosphere. Thus compounding is achieved, raising the efiiciency of the engine without the consumption of additional fuel, and at the same time the exhaust gases are permitted to exhaust to the atmosphere at a comparatively low pressure, thus greatly reducing the exhaust noise of the engine.

It will be appreciated that, because of the timing involved, it is not feasible to provide for direct communication at all times between the high and low pressure cylinders of the No. 1 cylinder and the low and high pressure cylinders of the No. 2 cylinder respectively, but that appreciable volumes of gas must be transferred from one to the other, so that the aforementioned revolving communicating means, both for scavenging and for exhaust, must not only function as a means of communication but must also, during part of the cycle, function as means for receiving and retaining a charge of gas of appreciable volume.

The above description has traced the passage of but a single charge of air which is subsequently burned with the fuel and converted into exhaust gases, and it will be understood that similar but cyclically displaced operations are taking place in all of the high and low pressure cylinders.

I have selected to illustrate and describe this invention as embodied in a counter-clockwise revolving four-cylinder engine consisting of two attached double units of two adjacent cylinder assemblies each, in which each of a pair of cylinders act in unison with each other in similar alternate functions, but it is obvious that many variations may be made in this general arrangement, it having been selected merely by way of illustration.

To the accomplishment of the above, and to such other objects as may hereinafter appear, the present invention relates to the construction and arrangement of a compound internal combustion engine as defined in the appended claims and as described in this specification, taken together with the accompanying drawings, in which:

Fig. 1 is a side elevational view of a four-cylinder engine, certain parts thereof being shown in section, cylinders No. 1 and No. 2 operating concurrently as a unit, with their respective cranks cyclically displaced 180 degrees from one another, cylinders No. 3 and N0. 4 likewise operating concurrently;

Fig. 2 is an end elevational view of the engine, showing the driving mechanism for the revolving communicating manifolds, the air starting mechanism, fuel pumps and engine controls;

Fig. 3 is a cross sectional view through one high pressure and low pressure cylinder and piston assembly showing the tandem arrangement of the pistons and cylinders, and also showing in section the scavenging and exhaust manifolds and some of the cylinder ports and passages communicating therewith;

Figs. 4, 5, 6 and 7 are schematic drawings of cylinders Nos. 1, 2, 3 and 4 respectively showing the various functions taking place in their respective high and low pressure cylinders at a given moment, a comparison of these figures illustrating the operations in any given cylinder at four separate points in a complete cycle for a given cylinder. The dotted lines with direction arrows in the ports and passages represent the ultimate air flow through those ports and passages, all as will be explained more in detail hereinafter;

Figs. 8 and 9 are diagrammatic views showing the functions of the pistons in the high and low pressure cylinders of cylinders No. 1 and No. 2 during one revolution of the crank shaft for the steps of ignition, high and low pressure power strokes, compression and exhaust;

Figs. 10 and 11 are diagrammatic views showing the functions of the pistons in the high and low pressure cylinders of cylinders No. 3 and No. 4 during one revolution of the crank shaft for the scavenging steps. Also demonstrated in Figs. 10 and 11 is the manner in which the engine may be started by compressed air admitted to act on the step pistons in the low pressure cylinders. It will be seen that the pressure of the gas in the high pressure cylinders is maintained in balance or equilibrium near the bottom of their stroke.

by the absence of all valves in the cylinder heads, thus preventing escape of the initial gases which, compressed on the up stroke, will re-expand on the down stroke until such time as combustion occurs; and

Fig. 12 is a diagrammatic view showing by lines, arrows and degrees the full cycle of operations occurring in each cooperating pair of cylinder assemblies in conjunction with the scavenging and exhaust communicating manifolds.

In the invention as here illustrated the cylinder assemblies are numbered consecutively from left to right as No. 1, No. 2, No. 3 and No. 4, adjacent cylinders No. l and No. 2 cooperating in their joint functions and 4 adjacent cylinders No. 3 and No. 4 doing likewise. In all of the figures the cranks, and hence the position of the pistons, bear the same relation to each other as shown in Figs. 4, 5, 6 and 7, namely, crank No. 1 is on top center, crank No. 2 is on bottom center, crank No. 3 is on half stroke rising, and crank No. 4 is on half stroke descending. All cranks are turning counter-clockwise. Also, throughout the specification a dual system of numerals has been adapted so as to distinguish between the adjoining cylinder assemblies, the parts relating to cylinders having even numbers being primed and the parts relating to cylinders having odd numbers being unprimed. The numeral 1 designates the base member or bedplate of the engine, which as above indicated may be designed for any number of multiples of two cylinder units depending upon the horse power required to be developed, each unit consisting of two high pressure cylinders in tandem with two low pressure or step cylinders. A housing 1 is provided which, when attached to the base member 1, forms individual enclosed crank cases 2, 2, one for each cylinder assembly. The high pressure cylinders 3, 3 are mounted on the housing 1',

and the low pressure cylinders 4, 4 are mounted inside the housing 1' in tandem alignment with the high pressure cylinders 3, 3'. As clearly shown in Fig. l, the cylinders and pistons are of tandem stepped form, that is to say, each high pressure cylinder 3, 3 and low pressure cylinder 4, 4' have aligned bores of different diameters, the smaller bore 3, 3' being the high pressure cylinder of'the engine, the larger bore 4, 4' being the low pressure power cylinder of each unit. Each high pressure cylinder 3, 3' is provided with a high pressure piston 5, 5' and each low pressure cylinder 4, 4' is provided with a low pressure step piston 6, 6'. As will be seen, the low pressure step cylinder 4, 4' with its step piston 6, 6' not only functions as the second stage power cylinder and piston on its down stroke, but also functions as the scavenging pump for the adjacent high pressure power cylinder 3', 3. In addition, when the motor is to be started or reversed compressed air is applied thereto.

Each high pressure cylinder 3, 3 is provided with the usual exhaust exit ports 13, 13' and air entry ports 10, 10', both being located in the side walls of the engine cylinders adjacent the lower ends thereof so as to be exposed by the high pressure pistons 5, 5 when the latter are at or near the bottom of their strokes. It will be noted that, departing from usual practice, the upper edges 10A, 10A of the air entry ports 10, 10' are higher than the upper edges of the opposed exhaust exit ports 13, 13. As a result supercharging of the high pressure cylinders can be effected, as indicated in Fig. 12.

Each low pressure or scavenging cylinder 4, 4 is provided with air entry ports 28, 28 and with final exhaust ports 44, 44' located in the cylinder walls adjacent the lower ends of the cylinders and adapted to be exposed by the low pressure pistons 6, 6 when the latter are at or The final exhaust ports 44, 44 serve a dual purpose. They permit the exhaust gases to escape to the atmosphere after they have produced the second power stage in the low pressure cylinders 4, 4', and they also provide for escape of the compressed air used for starting or reversing the engine after that air has served its purpose. The air intake ports 28, 28' permit air to enter the low pressure cylinders 4, 4' for the second scavenging stage, after the first stage scavenging pressure has been built up within the crank case 2, 2'.

Each piston assembly is provided with a connecting rod 7, mounted at its upper end on a Wrist pin 7 secured to the piston assembly and mounted at its lower end on crank pin 8 of the crank shaft 9, the latter having arms 8 to transmit power from the pistons thereto.

In order to describe the operation of the engine of the present invention it is deemed advisable to refer to the different sides of the engine as right hand and left hand respectively as viewed in Figs. 2 and 3, the front of the engine being that end visible in Fig. 2. For reasons which will become apparent hereinafter, the left hand side of the engine is the scavenging side and the right hand side thereof is the exhaust side.

On the scavenging or left hand side of the engine is mounted a manifold assembly comprising a cylindrical tubular casing 29, 29 with inlet ducts 30, 30 and outlet ducts 31, 31. As may clearly be seen from Figs. 4-7, these ducts line up respectively with the air inlet port branch passages 11, 11' in the high pressure cylinders 3, 3' and with the air exit passages 12, 12' leading from the low pressure cylinders 4, 4. Within this manifold casing 29, 29 is a hollow tubular fully revolving sleeve 32, 32' having attached thereto a central driving shaft 21, 21' which extends through the end covers 36, 36 of the casing 29, 29'. The shafts 21, 21' are caused to revolve in unison with the crank shaft by gearing or suitable chain drive. As shown in Fig. 2 a spiral gear 17 fast on vertical shaft 18 is driven by gear 16 on the crank shaft, the upper end of the shaft 18 carrying spiral gear 19 which meshes with another spiral gear 20 fast on the driving shaft 21. The hollow fully revolving scavenging manifold sleeve 32, 32' is provided with ports 33, 33' suitably located in its circumferential wall so as to coincide, at appropriate points in the cycle of operation, with the branch passages 39, 31) and 31, 31' in the casing 29, 29', so that when revolved it will define communication between the high and low pressure cylinders of adjacent pairs of cylinder assemblies, the scavenging air from each low pressure cylinder 4, 4 passing alternately backwards and forwards through the scavenging manifold into the appropriate high pressure cylinder 3, 3.

It will be noted particularly from Figs. 1 and 4-7, first, that because of its diameter and length the volume of the scavenging manifold 29 is appreciable when compared to the volume of the high pressure cylinders 3, 3', and second, that entry of air into the manifold 29 from, for example, the low pressure cylinder 4 is permitted, during the cycle of operation of the engine, at an appreciable time prior to the establishment of communication between the manifold 29 and the high pressure cylinder 3'. This is done while the low pressure piston 6 is rising, so that air is compressed within the scavenging manifold 29 prior to the time that it is released to enter the high pressure cylinder 3'. It will further be noted that as the sleeves 32, 32 rotate the timing of the opening and closing of the ports 33, 33' and 34, 34' are related to the opening and closing of the cylinder ports 10, by the high pressure pistons 5, 5 in their respective high pressure cylinders 3, 3', to the end that the appropriate cooperating ports are opened in timed coincidence.

On the right hand or exhaust side of the engine is a similar assembly of a cylindrical tubular exhaust communicating manifold casing 37, 37, shown in Fig. 2 as being water-jacketed. This exhaust manifold assembly forms a communicating connection between, and is attached to each pair of adjacent odd and even numbered assemblies. It is provided with an internal revolving sleeve 39, 39 so that the partially exhausted gases from the first stage power stroke will pass alternately backwards and forwards from each high pressure cylinder 3, 3' to the adjacent second stage cooperating low pressure cylinder 4', 4, the second stage power stroke thus being carried out by the partially exhausted gases acting on the larger area step pistons 6, 6'. Each high pressure cylinder 3, 3 has on its exhaust side, and passing through the exhaust manifold casing 37, 37 a duct or passage 14, 14 leading from the exhaust ports 13, 13 to the revolving sleeve 39, 39 within the exhaust manifold 37. To the lower end or base of the high pressure cylinders 3, 3 a second duct 15, communicates with ducts 38, 38' passing through the exhaust manifold casing 37, 37', these ducts forming a passage from the revolving sleeve 39, 39 directly to the low pressure step cylinders 4, 4'. The exhaust manifold revolving sleeve 39, 39' is driven by a shaft 26 extending horizontally through the manifold and covers 42, this shaft being connected to the crank shaft 9 by means of spiral gear 22, shaft 23 and spiral gears 25 and 24. The revolving sleeve 39, 39 within the exhaust manifold casing 37, 37' is provided with ports 40, 40' and 41, 41' passing through their circumferential walls and matching the port openings 14, 14 and 38, 38' in the manifold casing 37, 37', so that when the sleeve 39, 39 is rotated the coinciding ports will provide for communication of the exhaust gases from the high pressure cylinders 3, 3 to the low pressure cylinders 4, 4 respectively.

Considering now a given pair of associated cylinder as semblies, such as cylinders 1 and 2, it will be apparent that because the cranks of adjacent cylinder assemblies are cyclically degrees apart, the piston of No. 1 high pressure cylinder will be on bottom center exhausting, at the same time that the No. 2 low pressure step piston will be on top center ready to accept the exhaust from No. 1 high pressure cylinder. At the lowest point reached by the top edge of the low pressure pistons 6, 6' on their down stroke they will expose a row of circumferential ports 44, 44' passing through the back wall of the low pressure cylinders 4, 4, so as to permit the finally fully expanded exhaust gases to vent to the atmosphere via the passages 46, 46 and the final exhaust pipes 45, 45'. Because of the expansion of the exhaust gases in the second stage power stroke prior to exposure of the ports 44, 44', the exhaust gases will be at such a low pressure when finally vented to the atmosphere that the noise of the engine will be greatly reduced.

The wall of each enclosed crank case 2 is provided with an automatic inlet valve 27, 27', these being the only valves used in the entire engine. They are so designed as to prevent air from escaping from the crank case 2 but are effective, when the pressure in the crank case 2 is lower than that of the atmosphere, to permit air to enter the crank case 2, the valves 27, 27' thus opening automatically as the low pressure pistons 6, 6 move upward in their cylinders 4, 4', since the lower ends of the cylinders 4, 4' are open to the crank case 2. It is in this way that a charge of air is drawn into the crank case 2 on each cycle. In View of the fact that the underside of the low pressure piston 6, 6 has a much larger area than the high pressure cylinders 3, 3 and the same stroke, the volume of air or gas mixture drawn into the crank case 2 will exceed the volume of the high pressure cylinders 3, 3 by an amount suificient to ensure ample air for scavenging purposes plus an extra amount of air for sup ercharging.

The first stage of the scavenging operation occurs when air is drawn into the crank case 2. The second scavenging stage commences on the down stroke of the pistons 6, 6', the air in the crank case 2 being compressed and then forced through the transfer ports 28, 28', when the latter are exposed by the pistons 6, 6' into the low pressure cylinders 4, 4'. On the piston up stroke this charge of scavenging air is forced into the fully revolving scavenging manifold 32, 32 and then, at some time after air has commenced to enter that manifold, it will then be forced into the high pressure cylinder 3' via the ports 10. This process is repeated in reverse as the engine turns to force the scavenging air from the low pressure cylinder 4, the flow of scavenging air passing alternately backwards and forwards through the scavenging manifold 29, 29' as the engine operates. The No. 1 low pressure cylinder 4 scavenges and supercharges the No. 2 high pressure cylinder 3' and the No. 2 low pressure cylinder 4 scavenges and supercharges the No. 1 high pressure cylinder 3, the cylinders No. 1 and No. 2, adjacent and unitized, together carrying out a cooperative series of functions. Substantially the same sort of cooperative relationship exists with respect to the right hand or exhaust side of the No. 1 and No. 2 cylinders, the

7 V exhaust from the No. 1 high pressure cylinder 3 being fed to the No. 2 low pressure cylinder 4 for the second power stage, and the exhaust from the No. 2 high pressure cylinder 3 being fed to the No. 1 low pressure cylinder 4 for its second power stage.

It will be understood that the engine will also comprise conventional elements and features necessary or desirable in order that the engine should function, but since they are well known and form no specific part of the present invention they are not here specifically described. However, reference may be made, particularly in Fig. 2, to fuel pump 47, governor 48, fuel pump and governor drive 49, fuel pump pipe lines to the atomizer 50, the atomizer 51 and the air starting air main 54.

Operation Fig. 12 illustrates diagrammatically the manner in which the various pistons, cylinders, ports and manifolds function and cooperate. Different portions of the cycle are identified by reference numerals, the significance of those numerals being set forth below. As has been true throughout this specification, the primed numerals relate to occurrences in the No. 2 cylinder assembly and the unprimed numerals relate to occurrences in the No. 1 cylinder assembly.

55, 55'Crank case suction from atmosphere, beginning :first stage scavenging; crank travel 125 degrees.

56, 56'--First stage scavenging air compression in crankcase; crank travel 125 degrees.

57, 57'-Transfer of first stage scavenging air from crankcase to low pressure cylinders 4, 4'; crank travel 110 degrees.

58Second stage scavenging air compression in No. 2 low pressure cylinder 4' preparatory to delivery to No. 1 high pressure cylinder 3; crank travel 125 degrees.

58Second stage scavenging air compression in No. 1 low presspre cylinder 4 preparatory to delivery to No. 2 high pressure cylinder 3; crank travel 125 degrees.

59Second stage scavenging air delivery from No. 1 low pressure cylinder 4 through scavenging manifold 29 and its ports 3334' to No. 2 high pressure cylinder 3 entering same through ports 10'.

59-Second stage scavenging air delivery from No. 2 low pressure cylinder 4 through scavenging manifold 29 and its ports 33'34 to No. 1 high pressure cylinder 3, entering same through ports 10.

60, 60'--Delivery to and receiving of the second stage scavenging air into high pressure cylinders 3, 3 through the scavenging manifold 29, 29' via the cylinder ports 10, 10'; crank travel 110 degrees. It may be noted at this point that the upper edges 10A, 10A of the cylinder ports 10, 10' of the high pressure cylinders 3, 3' are extended above the top level of the exhaust ports 13, 13, to allow scavenging air, for a crank travel of 15 degrees, to enter the high pressure cylinders after the exhaust ports 13, 13' have been closed by the pistons 5, 5, this being permitted by the timing of the opening and closing of the ports 33--34, 33'-34', in the scavenging manifold relative to the opening and closing of the cylinder wall ports 10, by the pistons 5, 5'. Hence supercharging results for a designed period of degrees crank travel. Consequently in the present engine a full volume of scavenging and supercharging air is delivered to each of the high pressure power cylinders 3, 3 from the adjacent step or low pressure cylinder of the two cylinder unit.

60A, 60A'-Compression which takes place in the high pressure power cylinders, through a crank travel of 110 degrees.

61, 61'The ignition point in the high pressure cylinders No. l and No. 2.

62, 6'2'-The first stage power stroke; expansion in high pressure cylinders Nos. 1 and 2 through 125 degrees crank travel.

63 63'-First stage power stroke exhaust from high pressure cylinders 3, 3' to the revolving exhaust manifold 37, 37'; 110 degrees crank travel.

64, 64'-Diagonal lines and arrows showing exhaust from high pressure cylinders 3, 3' passing to and through the exhaust manifold 37, 37.

65, 65-Compounding, diagonal line and arrows showing exhaust from high pressure cylinders 3, 3', entering low pressure cylinders 4', 4 after passing through exhaust manifold 37, 37', to perform the second stage power stroke.

66, 66'Compounded, low pressure power stroke acting on low pressure step pistons 6, 6' in low pressure cylinders 4, 4, 125 degrees crank travel.

67, 67'Low pressure final exhaust to the atmosphere from low pressure cylinders 4, 4 through ports 44, 44' and exhaust pipe 45; 110 degrees crank travel.

68, 68-Starting air (compressed) acting on pistons of pressure cylinders 4, 4' entering said cylinders 45 degrees from top center of crankshaft cycle, and cutting ott degrees from top center.

69, 69-Starting (compressed) air expansion, after cut oil! in the low pressure cylinders 4, 4; from 90 degrees to 125 degrees from top center.

70, 70fiStarting (compressed) air exhaust from low pressure cylinders 4, 4 through ports 44 to exhaust pipe 45; degrees crank travel.

70A, 70ASupercharge air entering high pressure cylinders 3, 3' from low pressure cylinders 4', 4 after high pressure pistons 5, 5' have closed exhaust ports 13, 13'; 5 degrees crank travel.

In connection with the use of compressed air for starting or reversal, which compressed air is admitted to the low pressure cylinders 4, 4', as indicated by the reference numerals 68, 68 in Fig. 12, it should be noted that the pressure of the gases in the high pressure cylinders 3, 3' are maintained in balance or equilibrium (see particularly Figs. 10 and 11) because of the absence of all valves in the cylinder heads, thus preventing escape of the gases initially present in the high pressure cylinders 3, 3. Those gases compressed on the up stroke, will re-expand on the down stroke, thus giving rise to a balance of pressure in the high pressure cylinders 3, 3 until fuel is admitted and the engine is driven thereby. Once thls balance of pressure is established the force which the starting (compressed) air must exert on the low pressure pistons 6, 6' to keep the engine turning over need be only slightly greater than that necessary to overcome the friction of the moving parts. It has been shown by actual indicator cards that while p.s.i. pressure on the low pressure pistons 6, 6' produced 500 p.s.i. pressure In the adjacent high pressure cylinder 3, 3 during the first starting revolution, only 40 p.s.i. pressure on the piston 6' was required to keep the engine revolving until it took hold on fuel.

While the invention is here specifically disclosed in connection with a diesel type engine, it will be appreciated that many features are applicable to other types of internal combustion engines. Moreover, it will be apparent that the pressures involved and the cyclical relationships of the various parts may vary in different sizes or types of engines. In addition other variations may be made in details, all within the spirit of the present invention as defined in the following claims.

What I claim is:

l. A cross compound internal combustion engine comprising a pair of adjacent cylinder-piston assemblies, each assembly comprising a high pressure power cylinder and piston in tandem relation with a low pressure power cylinder and piston, said low pressure cylinders each having (a) substantially opposed air entry and final exhaust ports adjacent the lower end thereof, exposed and covered by the corresponding pistons and (b) first and second valveless open ports adjacent the upper end thereof for air exit and exhaust entry, respectively, said high pressure cylinders, each having substantially opposed ports adjacent the lower end then. of for air entry and exhaust exit respectively, exposed and covered by the corresponding pistons, a scavenging manifold connected in free fluid communication between said first valveless open ports of said low pressure cylinders and said air entry ports of said high pressure cylinders, an exhaust manifold connected in free fluid communication between said second valveless open ports of said low pressurecylinders and said exhaust exit ports of said high pressure cylinders, flow controlling means operatively associated with each manifold, operatively connected to said ports with which said manifold is connected, and controlling fluid flow through said ports, and means for actuating said flow controlling means in synchronism with the movement of said pistons to separately provide communication through said manifolds, first between the low pressure cylinder of one assembly and the high pressure cylinder of the other assembly and then between the low pressure cylinder of said other assembly and the high pressure cylinder of said one assembly, whereby air in said scavenging manifold and exhaust in said exhaust manifold passes successively therethrough in different directions, said manifolds defining the only fluid connections between the parts to which they are connected and having no external connections other than those specified, means interconnecting the pistons of said adjacent assemblies to cause the pistons of one of said assemblies to operate substantially 180 degrees out of phase with the pistons of the other of said assemblies, said actuating means being operatively connected to said interconnecting means so as to be operated thereby, and means for admitting precompressed air to the air entry ports of said low pressure cylinders.

2. The engine of claim 1, in which said actuating means, in the course of providing communication between a high pressure and a low pressure cylinder permits entry of fluid into said manifold from the cylinder then feeding said manifold while closing off all other ports from said manifold, and thereafter, while permitting fluid to continue to enter said manifold from said feeding cylinder, establishes communication between said manifold and the cylinder then to be fed.

3. The engine of claim 2, in which said manifold has an appreciable volume when compared to the volume of said high pressure cylinders.

4. The engine of claim 2, in which said actuating means, on each step of the cycle, commences to establish communication between said manifold and the operative piston-exposed port of the appropriate cylinder at substantially the same moment as said port commences to be exposed by said piston.

5. The engine of claim 2, in which said actuating means is effective, on each step of the cycle, commences to establish communication between said manifold and the operative piston-exposed port of the appropriate cylinder at substantially the same moment as said port commences to be exposed by said piston, said manifold having an appreciable volume when compared to the volume of said high pressure cylinders.

6. The engine of claim 1, in which said actuating means, on each step of the cycle, commences to establish communication between said manifold and the operative piston-exposed port of the appropriate cylinder at substantially the same moment as said port commences to be exposed by said piston.

7. The engine of claim 1, in which said manifold has an appreciable volume when compared to the volume of said high pressure cylinders.

8. The engine of claim 1, in which each cylinderpiston assembly has a separate air-tight chamber in com munication with the lower and open end of its low pressure cylinder, a one-way valve actuated by pressure differential communicating between said chamber and an outside source of gas and. effective to permit gas only to enter said chamber, and air passage means between said chamber and the air entry port of said low pressure cylinder.

9. A cross compound internal combustion engine comprising a pair of adjacent cylinder-piston assemblies, each assembly comprising a high pressure power cylinder and piston in tandem relation with a low pressure power cylinder and piston, said low pressure cylinders each having (a) substantially opposed air entry and final exhaust ports adjacent the lower end thereof, exposed and covered by the corresponding pistons and (b) first and second valveless open ports adjacent the upper end thereof for air exit and exhaust entry respectively, said high pressure cylinders each having substantially opposed ports adjacent the lower end thereof for air entry and exhaust exit respectively, exposed and covered by the corresponding pistons, a scavenging manifold connected in free fluid communication between said first valveless open ports of said low pressure cylinders and said air entry ports of said high pressure cylinders, an exhaust manifold connected in free fluid communication between said second valveless open ports of said low pressure cylinders and said exhaust exit ports of said high pressure cylinders, a rotating element in each manifold carrying ports adapted to register with the ports with which said manifold is connected, and means for rotating said elements in synchronism with the movement of said pistons, said ports on said elements and said ports with which said manifolds are connected cooperating as said elements rotate to successively and separately provide communication through the manifolds, first between the low pressure cylinder of one assembly and the high pressure cylinder of the other assembly and then between the low pressure cylinder of said other assembly and the high pressure cylinder of said one assembly, whereby air in said scavenging manifold and exhaust in said exhaust manifold passes successively therethrough in different directions, said manifolds defining the only fluid connections between the parts to which they are connected and having no external connections other than those specified, means interconnecting the pistons of said adjacent assemblies to cause the pistons of one of said assemblies to operate substantially degrees out of phase with the pistons of the other of said assemblies, said means for rotating said elements being operatively connected to said interconnecting means so as to be operated thereby, and means for admitting precompressed air to the air entry ports of said low pressure cylinders.

10. The engine of claim 9, in which said ports on said revolving manifold elements first permit entry of fluid into said manifold from the cylinder then adapted to feed said manifold while closing off all other ports from said 'manifold, and thereafter, while permitting fluid to continue to enter said manifold from said feeding cylinder, opening the port to the cylinder then to be fed by said manifold to establish said communication.

11. The engine of claim 10, in which said manifold has an appreciable volume when compared to the volume of said high pressure cylinders.

12. The engine of claim 10, in which said ports on said revolving manifold elements, on each step of the cycle, commence to open the operative piston-exposed port at substantially the same moment as said port commences to be exposed by its cooperating piston.

13. The engine of claim 10, in which said ports on said revolving manifold elements, on each step of the cycle, commence to open the operative piston-exposed port at substantially the same moment as said port commences to be exposed by its cooperating piston, said manifold having an appreciable volume when compared to the volume of said high pressure cylinders.

14. The engine of claim 9, in which said ports on said revolving manifold elements, on each step of the cycle, commence to open the operative piston-exposed port at substantially the same moment as said port commences to be exposed by its cooperating piston.

15. The cylinder of claim 9, in which said manifold has an appreciable volume when compared to the volume of said high pressure cylinders.

16. The engine of claim 9, in which each cylinderpiston assembly has a separate air-tight chamber in communication with the lower and open end of its low pressure cylinder, a one-way valve actuated by pressure differential communicating between said chamber and an outside source of gas and eflective to permit gas only to enter said chamber, and air passage means between said chamber and the air entry port of said low pressure cylinder.

UNITED STATES PATENTS Davison May 11, Fothergill June 27, Carbone et a1. Dec. 7, Kline Aug. 9, Mantle Mar. 12, Auriol Feb. 16, Brunnschweiler Mar. 15, Lindberg Apr. 18, Winfield July 5, Waring July 3, Black Dec. 13, Bryant Apr. 15,

FOREIGN PATENTS Great Britain Apr. 24, 

